Carriage roller adjusting mechanism for stairlifts

ABSTRACT

An apparatus for adjusting the rollers of a stairlift carriage, for ensuring that the carriage is firmly located on a stairlift rail, includes rollers for engaging one side of the stairlift rail, as well as rollers located on an opposite side of the rail, such that the stairlift rail is located between opposed sets of rollers. To achieve adjustment, the rollers on one side of the rail are located on a common member, which can be displaced toward and away from the stairlift rail.

FIELD OF THE INVENTION

This invention relates to stair mounted elevators or lifts, commonlyknown as stairlifts.

BACKGROUND

Stairlifts, in the form of a carriage mounted for movement along a rail,are well known for moving aged or handicapped persons up and downstaircases.

In our pending International Patent Application PCT/GB99/03447 wedescribe and claim a form of stairlift in which the stairlift carriageis supported on a narrow tubular rail including four rolling surfacesarranged about the rail cross-section at 45° to a horizontal planethrough the rail. To this end, the carriage includes roller pairs whichbear on the rolling surfaces extending along the rail, and the aboveapplication describes how these rollers are provided in upper and lowerpairs. The pending application further describes the use of axle pinsmounted in eccentric through bores in the lower rollers which allowsadjustment of the lower rollers to take up unwanted play between thecarriage and the rail.

In practice, we have found that the particular rail and carriageconfiguration does not best lend itself to adjustment in the mannerdescribed. Further, accessing and manipulating the eccentric mounts ofthe lower rollers can be difficult for an installer.

It is an object of this invention to provide a stairlift which allowsadjustment in installation and/or operation which addresses theaforementioned problems, or which will at least provides a usefulchoice.

SUMMARY OF THE INVENTION

Accordingly, in one aspect, the invention provides a stairlift carriagefor movement along a stairlift rail, said carriage including:

a plurality of first rollers arranged to engage said rail from a firstdirection;

a plurality of second rollers arranged to engage said rail from a seconddirection, said second direction being substantially opposed to saidfirst direction; and

adjustment means operable to adjust the spacing between at some of saidfirst rollers and said second rollers, said carriage being characterisedin that said adjustment means includes a common member on which at leasttwo of said first rollers are mounted and displacement means operable todisplace said common member towards said second rollers.

Preferably all of said first rollers are mounted on said common member.

Preferably said carriage further includes a spaced pair of side plateswhich, when said carriage is in its normal operating position, overlieopposite sides of said rail, wherein said rollers are mounted to projectinwardly from said side plates.

Preferably said displacement means is operable to displace said commonmember with respect to the side plate from which said first rollersproject. Said displacement means conveniently comprises one or more grubscrews, each grub screw being mounted in a stud fixed to said sideplate.

In a second aspect the invention provides a stairlift including thecarriage as herein before set forth.

Many variations in the way the present invention may be performed willpresent themselves to those skilled in the art. The description whichfollows is intended as an illustration only and the absence ofdescription of particular alternatives or variants should in no way beapplied to limit the scope of the invention. Such description ofspecific elements which follows should also be interpreted as includingequivalents whether existing now or in the future. The scope of theinvention should be defined solely by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

One form of stairlift carriage incorporating the invention will now bedescribed with reference to the accompanying drawings in which:

FIG. 1: Shows an end sectional view of a stairlift carriageincorporating the invention mounted on a stairlift rail;

FIG. 2: Shows, in a smaller scale, a view along the line II—II in FIG. 1with certain components omitted for clarity;

FIG. 3: Shows, in a larger scale than FIG. 2, a view along the line A—Ain FIG. 2; and

FIG. 4: Shows, in a larger scale than FIG. 2, a view along the line B—Bin FIG. 2.

DESCRIPTION OF WORKING EMBODIMENT

Referring firstly to FIG. 1, the present invention provides a stairliftcarriage 10 mounted substantially above, for movement along, a tubularrail 11 of constant cross section. The carriage is supported on the railby a first roller set 12 and a second roller set 13 and it will beappreciated that the roller sets 12 and 13 engage opposite sides of therail and from substantially opposite directions.

The rail and roller configuration is such as to permit smooth movementof the carriage longitudinally of the rail yet prevent tilting, skewingand rotation of the carriage about the rail.

In the form shown, each of the roller sets 12 and 13 comprises fourrollers, the first set 12 being shown in entirety in FIG. 2 andcomprising individual roller pairs 12 a, 12 b and 12 c and 12 d, therollers 12 c and 12 d being mounted to engage the rail at a positionlongitudinally spaced from that engaged by the rollers 12 a and 12 b.

The roller set 13 is a mirror of the roller set 12.

In accordance with conventional practice, the rail 11 has a plurality ofrolling surfaces 14, 15, 16 and 17 for rolling engagement by the rollersets 12 and 13. As can be seen, the rolling surfaces are arranged aboutthe cross section of the tubular rail, extend longitudinally of the rail11 and are formed by the same elements that define the structuralelements of the tube. This leads to a compact and structurally efficientrail.

In the form shown, rollers 12 a and 12 d engage rolling surface 14,rollers 12 b and 12 c engage rolling surface 15, rollers 13 b and 13 cengage rolling surface 16 and rollers 13 a and 13 d engage rollingsurface 17.

As shown, the carriage 10 further includes a main chassis 20 which, whenthe carriage is mounted in position on the rail 11, spans over the rail.Mounted at spaced points on the chassis 20, preferably along oppositeedges of the chassis, are side plates 21 and 22 which extend down tooverlie at least part of both sides of the rail 11. As will be describedin greater detail below, the side plates also serve as mountings for theroller sets 12 and 13.

Included on the chassis 20 is a mounting base 23 which is angled to theremainder of the chassis and serves as a mounting surface for main drivemotor 24 and gearbox 25. The chassis 20 further includes a centralaperture 26. This gives clearance to enable drive pinion 28, mounted onoutput shaft 27 of gearbox 25, to engage with drive rack 29 locatedbelow the chassis 20 on rail 11. Rotation of the pinion 28 causes thecarriage 10 to be displaced along the rail 11.

The lower part of side plate 22 is preferably provided with an internaltriangulated bracing member 30, the bracing member extending along thecarriage and adding considerable stiffness to that section of thecarriage which provides the mount to the rail 11. As can be seen, thebracing member also provides convenient mounting points for the secondrollers 13. Indeed, the configuration of bracing which providessignificant natural strength—a triangle—also perfectly positions therollers 13 a, 13 b, 13 c and 13 d to engage the perpendicular rollingsurfaces 16 and 17 of the rail 11.

In order to provide adjustment between the rollers 12, 13 and the rail11, the first rollers 12 are mounted for movement toward and away fromthe rollers 13. To this end, at least some, and preferably all, of therollers 12 are mounted on a common member or bogie 31 which, in turn, ismounted on the inner surface of side plate 21 for movement toward andaway from the side plate 21 and away from and toward the roller set 13.

Referring now to FIGS. 2 to 4, the bogie 31 has a solid centre section32 of rectangular cross-section and two end sections 33 a and 33 b oftriangular section, the rollers 12 being mounted on the end sections 33a, 33 b so as to mirror the configuration of the rollers 13. As can beseen from FIG. 4, each of the rollers 12 (and indeed each of the rollers13) is mounted on an axle pin 34 via a roller bearing 35. Each axle pin34 is screwed into threaded bores 36 provided in end sections 33 ofbogie 31.

Referring now to FIG. 3, the centre section 32 of bogie 31 includes apair of spaced bores 37 which slidingly receive a pair of studs 38 fixedto, and projecting inwardly from, the side plate 21. Screw fitted into acentral bore 39 in each stud 38 is a grub screw 40 and it will beappreciated that as the grub screws 40 are screwed into bores 39, thebogie 31 is displaced away from the inner surface of side plate 21.Simultaneously, the rollers 12 are displaced toward the rollers 13 tomore firmly clamp the carriage 10 onto rail 11.

Once the desired roller adjustment has been achieved, the bogie 31 maybe locked in place by locking bolts 41 (FIG. 2) which pass through endtabs 42 of a fixing plate 43 fixed to side plate 21, and engage in boresdrilled in the end faces of the end sections 33 a and 33 b.

Although the bogie 31 has been described as a single component, it couldbe provided in two parts with one pair of rollers on each part.

In use, the installer sets the carriage 10 on the rail 11 which he haspreviously mounted on the stair. The carriage is preferably mounted sothat the side plate 22 is adjacent one wall defining the stairway andthe side plate 21 is on the outside of the installation. The installercan then tighten the carriage 10 on the rail 11 by inserting an Allenkey into each bore 39 in turn and causing bogie 31 to be displaced awayfrom side plate 21 until the rollers pairs 12 and 13 are firmly yetrotatably engaged with opposite sides of the rail 11. Once the bogie 31has been positioned correctly, the installer tightens bolts 41 to lockthe bogie with respect to the side plate 21.

It will thus be appreciated that the present invention, at least in thecase of the embodiment thereof described above, provides a simple yeteffective means of providing for roller adjustment to be effected on astairlift installation from a position easily accessed by an installer.

What is claimed is:
 1. A stairlift carriage for movement along astairlift rail, said stairlift carriage comprising: a plurality of firstrollers arranged for engaging a stairlift rail from a first direction; aplurality of second rollers arranged for engaging said stairlift railfrom a second direction, said second direction being substantiallyopposite to said first direction; and, means for adjusting a spacingbetween at least some of said plurality of first rollers and saidplurality of second rollers, said means for adjusting including: acommon member on which at least two of said plurality of first rollersare mounted; and, means for displacing said common member toward saidplurality of second rollers.
 2. The stairlift carriage for movementalong a stairlift rail according to claim 1, wherein all of saidplurality of first rollers are mounted on said common member.
 3. Thestairlift carriage for movement along a stairlift rail according toclaim 1, further comprising a spaced pair of side plates overlyingopposite sides of said stairlift rail when said stairlift carriage is inits operating position, said plurality of first rollers and saidplurality of second rollers being mounted for projecting inwardly fromsaid spaced pair of side plates.
 4. The stairlift carriage for movementalong a stairlift rail according to claim 3, wherein said means fordisplacing said common member displaces said common member relative toone side plate of said spaced pair of side plates from which saidplurality of first rollers project.
 5. The stairlift carriage formovement along a stairlift rail according to claim 4, where in saidmeans for displacing said common member includes at least one grub screwmounted in a stud fixed to said one side plate.
 6. A stairlift,comprising: a stairlift rail; and, a carriage for movement along saidstairlift rail, said carriage including: a plurality of first rollersarranged for engaging said stairlift rail from a first direction; aplurality of second rollers arranged for engaging said stairlift railfrom a second direction, said second direction being substantiallyopposite to said first direction; and, means for adjusting a spacingbetween at least some of said plurality of first rollers and saidplurality of second rollers, said means for adjusting including: acommon member on which at least two of said plurality of first rollersare mounted; and, means for displacing said common member toward saidplurality of second rollers.